#include<bits/stdc++.h>
using namespace std;
int main(){
int arr[6]={1,1,2,2,2,1};
unordered_map<int,int>hmap;
int diff=0;
for(int i=0;i<6;i++){
if(hmap.find(arr[i])==hmap.end()){
hmap[arr[i]]=i;
}
else{
diff=max(diff,i-hmap[arr[i]]);
}
}
cout<< diff;
}
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