#include <stdio.h>
#include <string.h>
int main() {
	int A,B;
	scanf("%d %d",&A,&B);
	getchar();
	
	char S[A+B+2] = {0};
	scanf("%s",&S);
	int len = strlen(S);
	int flag = 0;
	
	for (int i = 0; i < len; i++)
	{
		if (48 <= S[i] && S[i] <= 57)
		{
			flag = 1;
		}
		else
		{
			if ( i == 45 )
			{
				flag = 0;
				continue;
			}
			else if (i != 45)
			{
				flag = 0;
				break;
			}
		}
	}
	
	flag ? printf("Yes\n") : printf("No\n");
	
	return 0;
}