"""
author : halo2halo
date : 24, Jan, 2020
"""

import sys

# import itertools
# import numpy as np

read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
sys.setrecursionlimit(10 ** 7)

A, B = map(int, readline().split())
S = readline().decode('utf8').rstrip()

print('Yes' if S[A] == '-' and (S[:A] + S[A + 1:]).find('-') else 'No')
