#include <iostream>
using namespace std;
int main() {
int arr[]= {1, 5, 3, 4, 2};
int n=sizeof(arr)/sizeof(arr[0]);
int diff=2;
int count=0;
for(int i=0;i<n-1;i++){
for(int j=i+1;j<n;j++){
if(abs(arr[i]-arr[j])==diff)
count++;
}
}
cout<<count;
}
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