diff --git a/prob2.c b/prob2.c
new file mode 100644
index 0000000..922bbbe
--- /dev/null
+++ b/prob2.c
@@ -0,0 +1,23 @@
+#include<stdio.h>
+int main()
+{
+    int i,n,count=0;
+    scanf("%d",&n);
+    int ar1[1000000];
+    int ar2[2000001];
+    for(i=0;i<2000001;i++)
+        ar2[i]=0;
+    for(i=0;i<n;i++)
+    {
+        scanf("%d",&ar1[i]);
+                int c=ar1[i]+1000000;
+              ar2[c]++;
+    }
+     for(i=0;i<2000001;i++)
+         {
+         if(ar2[i]>1)
+         count++;
+         }
+         printf("%d\n",count);
+    return 0;
+}
diff --git a/prob3.c b/prob3.c
new file mode 100644
index 0000000..ff10e5a
--- /dev/null
+++ b/prob3.c
@@ -0,0 +1,57 @@
+#include<stdio.h>
+void merge(int arr[],int l,int m,int r)
+{
+    int i,j,k;
+    int n1 = m - l + 1;
+    int n2 = r - m;
+    int L[n1], R[n2];
+    for(i=0;i<n1;i++) L[i]=arr[i+l];
+    for(j=0;j<n2;j++) R[j]=arr[j+m+1];
+    i=j=0;
+    k=l;
+    while(i<n1 && j<n2)
+    {
+        if(L[i]<=R[j]) arr[k]=L[i++];
+        else arr[k]=R[j++];
+        k++;
+    }
+
+    while(i<n1) arr[k++]=L[i++];
+    while(j<n2) arr[k++]=R[j++];
+}
+void merge_sort(int arr[],int l,int r)
+{
+    if(l<r)
+    {
+        int m;
+        m = l + (r-l)/2;
+        merge_sort(arr,l,m);
+        merge_sort(arr,m+1,r);
+        merge(arr,l,m,r);
+    }
+}
+int main()
+{
+    int i,n,comp,temp;
+    int a,b;
+    int arr[1000000];
+    scanf("%d",&n);
+    for(i=0;i<n;i++)
+        scanf("%d",&arr[i]);
+    merge_sort(arr,0,n-1);
+    comp=arr[1]-arr[0];
+    a=arr[0];
+    b=arr[1];
+    for(i=2;i<n;i++)
+    {
+        temp=arr[i]-arr[i-1];
+        if(temp<comp)
+        {
+            comp=temp;
+            a=arr[i-1];
+            b=arr[i];
+        }
+    }
+    printf("%d %d\n",a,b);
+    return 0;
+}
diff --git a/prob5.c b/prob5.c
new file mode 100644
index 0000000..da9ced5
--- /dev/null
+++ b/prob5.c
@@ -0,0 +1,60 @@
+#include<stdio.h>
+void merge(long long int arr[],int l,int m,int r);
+void merge_sort(long long int arr[],int l,int r);
+void merge(long long int arr[],int l,int m,int r)
+{
+    int i,j,k;
+    int n1 = m - l + 1;
+    int n2 = r - m;
+    int L[n1], R[n2];
+    for(i=0;i<n1;i++) L[i]=arr[i+l];
+    for(j=0;j<n2;j++) R[j]=arr[j+m+1];
+    i=j=0;
+    k=l;
+    while(i<n1 && j<n2)
+    {
+        if(L[i]>=R[j]) arr[k]=L[i++];
+        else arr[k]=R[j++];
+        k++;
+    }
+
+    while(i<n1) arr[k++]=L[i++];
+    while(j<n2) arr[k++]=R[j++];
+}
+void merge_sort(long long int arr[],int l,int r)
+{
+    if(l<r)
+    {
+        int m;
+        m = l + (r-l)/2;
+        merge_sort(arr,l,m);
+        merge_sort(arr,m+1,r);
+        merge(arr,l,m,r);
+    }
+}
+int main()
+{
+    int i,n;
+    long long arr[1000000];
+    long long sum,c;
+        sum=0;
+        scanf("%d",&n);
+        for(i=0;i<n;i++)
+        {
+            scanf("%lld",&arr[i]);
+            sum+=arr[i];
+        }
+        merge_sort(arr,0,n-1);
+        for(i=1;i<n;i++)
+            arr[i]+=arr[i-1];
+        for(i=0;i<n;i++)
+        {
+            c=arr[i];
+            if((long long)2*c>=sum)
+            {
+                printf("%d\n",i+1);
+                break;
+            }
+        }
+    return 0;
+}