#include <iostream>
#include <math.h>
#include <algorithm>
#include <string>
#include <vector>
#include <string.h>
using namespace std;

int main() {
	int A,B;
	bool ans=true;
	string S;
	cin>>A>>B;
	cin>>S;
	for(int i=0;i<size(S);i++)
	{
		if(i==A&&S[i]!='-')ans=false;
		else if(!(S[i]-'0'>=0&&S[i]-'0'<=9))ans=false;
	}
	cout<<((ans)?"Yes":"No");
	}