题目地址：
http://coder.buct.edu.cn/oj/Problem.aspx?pid=1216

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#include <iostream>
using namespace std;
 
__int64 gcd(__int64 a, __int64 b)
{
    if(a<b)
    {
        a ^= b;
        b ^= a;
        a ^= b;
    }
    if(b == 0)
        return a;
    return gcd(b, a%b);
}
 
int main()
{
	int nCases, nNum;
	scanf("%d", &nCases);
	while(nCases--)
	{
		__int64 res=1, tmp;
		scanf("%d", &nNum);
		for(int i=0; i<nNum; ++i)
		{
			scanf("%I64d", &tmp);
			res = res*tmp/gcd(tmp, res);
		}
		if(res > 1000000000)
			printf("More than a billion.\n");
		else
			printf("%I64d\n", res);
 
	}
	return 0;
}