#include<bits/stdc++.h>
using namespace std;
int main()
{
	int a,b;
	cin >> a >> b;
	string s;
	cin >> s;
	if(s[a] != '-')
	{
		puts("No");
		return 0;
	}
	for(int i=0;i<a+b+1;i++)
		if(i != a && (s[i]<'0' || s[i]>'9' ) )
		{
			puts("No");
			return 0;
		}
	puts("Yes");
	return 0;		
}