#include <bits/stdc++.h>
using namespace std;
#define sim template < class c
#define ris return * this
#define dor > debug & operator <<
#define eni(x) sim > typename \
  enable_if<sizeof dud<c>(0) x 1, debug&>::type operator<<(c i) {
sim > struct rge { c b, e; };
sim > rge<c> range(c i, c j) { return rge<c>{i, j}; }
sim > auto dud(c* x) -> decltype(cerr << *x, 0);
sim > char dud(...);
struct debug {
#ifdef LOCAL
~debug() { cerr << endl; }
eni(!=) cerr << boolalpha << i; ris; }
eni(==) ris << range(begin(i), end(i)); }
sim, class b dor(pair < b, c > d) {
  ris << "(" << d.first << ", " << d.second << ")";
}
sim dor(rge<c> d) {
  *this << "[";
  for (auto it = d.b; it != d.e; ++it)
	*this << ", " + 2 * (it == d.b) << *it;
  ris << "]";
}
#else
sim dor(const c&) { ris; }
#endif
};
#define imie(...) " [" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "

int main() {
	int a, b;
	cin >> a >> b;
	int total = 2 * a + 100;
	cout << total - b << "\n";
}

/*Arnab's Code
*/
#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define mp(a,b) make_pair(a,b)
#define vll vector<ll>
#define vii vector<int>
#define pll pair<ll,ll>
#define pii pair<int,int>
#define take(a,n) for(ll i=0;i<n;i++)cin>>a[i]
#define takes(a,n,st) for(ll i=st;i<n+st;i++)cin>>a[i]
ll sum(ll a[],ll n,ll s){ for(ll i=0;i<n;i++)s+=a[i]; return s;}
#define mod 1000000009
ll power(ll x, ll y, ll p)  {  
    ll res = 1;  
    x = x % p;   
    if (x == 0) return 0;  
    while (y > 0){  
        if (y & 1)  
            res = (res*x) % p;  
        y = y>>1;
        x = (x*x) % p;  
    }  
    return res;  
}
void solve(){
	ll a,b,c;
	cin>>a>>b;
	c=(2*a)+100;
	cout<<abs(c-b);
	return;
}
int main(){
	ios::sync_with_stdio(false);
	cin.tie(NULL);
	#ifndef ONLINE_JUDGE
		freopen("input.txt","r",stdin);
		freopen("output.txt","w",stdout);
	#endif
	ll t,T;
//	cin>>T;
	T=1;
	for(t=1;t<=T;t++){
//		cout<<"Case #"<<t<<": ";
		solve();
	}
	return 0;
}
