include<bits/stdc++.h>

using namespace std;

int check(int n){
int num = n % 10;
n /= 10;
while (n)
{
if(n % 10 != num){
return false;
}
n/= 10;
}
return true;
}
int main(){
long long x ;
cin >> x ;
long long n = x;
while (check(n) == false){
++n;
}
int s = n - x;
cout << s << endl;
system("pause");
}
// 123 23