#include<bits/stdc++.h>
#define ll long long int
#define pb push_back
#define ppb pop_back
#define fast_io ios_base::sync_with_stdio(false);cin.tie(NULL)
#define fr(a,b) for(int i = a; i < b; i++)
#define rep(i,a,b) for(int i=a;i<b;i++)
#define all(x) (x).begin(),(x).end()
#define ppc __builtin_popcount
#define ppcll __builtin_popcountll
#define mem1(a) memset(a,-1,sizeof(a))
#define mem0(a) memset(a,0,sizeof(a))
#define endl '\n'
using namespace std;
const ll MOD=1e9+7;
const ll INF= 998244353;
const ll N=1e6+1;

/*ll fact(ll n) 
{ 
    ll res = 1; 
    for (ll i = 2; i <= n; i++) 
        res = res * i; 
    return res; 
}

ll nCr(ll n, ll r) 
{ 
    return fact(n) / (fact(r) * fact(n - r)); 
} 
// Returns factorial of n
*/
/*ll gcd(ll a, ll b)
{
  if(b==0)
    return a;
  return gcd(b,a%b);
}
ll lcm(ll a,ll b)
{
  return (a*b)/gcd(a,b);
}

*/
/*bool isprime(ll n)
{
  ll i;
  for(i=2;i*i<=n;i++)
  {
    if(n%i==0)
    {
      return false;
    }
  }
  return true;
}*/

void solve()
{
  ll n;
  cin>>n;
  ll num=(n/100)+1;
  cout<<abs((num*100)-n)<<endl;
}

int main()
{
  fast_io;
  cin.tie(0);cout.tie(0);
  ll t;
  t=1;
  //cin>>t;
  while(t--)
  {
    solve();
  }
  return 0;  
}



#include <iostream>
#include <cstdio>
#include <algorithm>

using namespace std;

int main()
{
    int n; cin >> n;
    int d = n % 1000;
    int p = n / 100 % 10 + 1; p *= 100;
    cout << p - d << "\n";
    return 0;
}