c++lcm(m,n)直接用c++的内置函数lcm(m,n )
,2641(unsignedlonglong)注意审题,题目中的范围是2^{64}-1(unsigned long long范围内)

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

int main()
{
	unsigned long long a,b;
    cin>>a>>b;
    cout<<lcm(a,b);
    return 0;
}