#include <iostream>
using namespace std;

int main() {
    int a, b;
    cin >> a >> b;
    int max = (a > b) ? a : b;
    while (true) {
        if (max % a == 0 && max % b == 0) {
            cout << max << endl;
            break;
        }
        max++;
    }
    return 0;
}

网上搜的

#include<bits/stdc++.h>
using namespace std;
int main(){
  	int i,a,b;
  	cin>>a>>b;
  	if(a>b){
	  	for(i=a;i<=a*b;i++){
		  	if(i%a==0 and i%b==0){
			  	break;
			}
		}
	}
	else{
		for(int i=b;i<=a*b;i++){
		  	if(i%a==0 and i%b==0){
			  	break;
			}
		}
	}
	cout<<i;
	return 0;
}