#include<bits/stdc++.h>
using namespace std;
int main()
{
	int m,n=1,t=0;
	cin>>m;
	while(m>t)
	{
		t+=n;
		n++;
	}
	cout<<n-1;
	return 0;
}
快给下面的差评，反正你们不玩司马懿！

#include <bits/stdc++.h> using namespace std; int main (){ int n,m; cin>>m; 1<=m<=10000; n=(-1+sqrt(1+8m))/2; if(n(n+1)/2!=m){ n=n+1; cout<<n; }else{ cout<<n; } return 0; }

差评者司马