#include <bits/stdc++.h>
 
#define                 ll long long
#define in(a)           for (auto &x : a) cin >> x;
#define out(a)          for (auto x : a) cout << x << ' ';  cout << endl;
#define loop(i, l, n)   for(int i=(l); i<(n); i++)
#define mod             1000000007
#define yes             cout<<"YES"<<endl
#define no              cout<<"NO"<<endl
#define so              cout<<100<<endl
#define f first
#define s second
#define pb push_back
#define mp make_pair
 
 
 
using namespace std;
 
 
void solve()
{
 
}
 
int main()
{
    long long int a;
    cin>>a;
    cout<<a-1971<<endl;
}