#include<iostream>
#include<string.h>
using namespace std;
int a,b,m;
char str[1000];
int main(){
	while(scanf("%d%d",&a,&b)!=EOF){
		scanf("%s",str);
		while(str[i]!='-'){
			i++;
		}
		if((strlen(str)==a+b+1)&&i==a){
		cout<<"Yes"<<endl;
	}else{
		cout<<"No"<<endl;
	}
}
	return 0;
}