// editor1
#include<stdio.h>
int findPivotIndex(int arr[],int n){
    int totalSum=0,leftSum=0;
    for(int i=0;i<n;i++){
        totalSum+=arr[i];
    }
     for(int i=0;i<n;i++){
       int rightSum=totalSum-leftSum-arr[i];
       if(leftSum == rightSum){
           return i;
       }
       leftSum+=arr[i];
   }
   return -1;
}
int main(){
    int n;
    scanf("%d",&n);
    int arr[n];
    for(int i=0;i<n;i++){
        scanf("%d",&arr[i]);
    }
    int pivot = findPivotIndex(arr,n);
    if(pivot!=-1){
        printf("%d",pivot);
    }else{
        printf("No Pivot Input")
    }
    return 0;
}