#include <bits/stdc++.h>
#define FOR(i, a, b) for(int i = a; i <= b; ++i)
using namespace std;
#define int long long
const int _ = 2e6+6;
bool check(int mid,int n,int m) {
    int tot=mid*5;
    int need=n+m-min(min(n,m),mid*4);
    if(tot>=need) return 1;
    return 0;
}
signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n,m;
    cin>>n>>m;
    int l=0,r=n+m,ans=0;
    while(l<=r) {
        int mid=(l+r)>>1;
        if(check(mid,n,m)) {
            r=mid-1;
            ans=mid;
        } else {
            l=mid+1;
        }
    }   
    ans=(ans-1)*2+1;
    cout<<ans<<"\n";
    return 0;
}