#include <bits/stdc++.h>
using namespace std;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    
    long long N,M; cin >> N >> M;
    if(N%2 == 0){cout << N*M << endl; return 0;}
    if(N == 1){cout << 0 << endl; return 0;}
    long long answer = 0;
    long long same = N,under = 0;
    for(int i=30; i>=0; i--){
        if(M&(1<<i)){
            if(same > 0) same--,under++;
            answer += (N/2*2)<<i;
        }
        else{
            answer += (under/2*2)<<i;
        }
    }
    cout << answer << endl;
}