a, b = [int(x) for x in input().split()]
num = '0123456789'
S = input()
flg = True
for i in len(S):
  if i == a:
    if not S[i] == '-':
      flg = False
  else:
    if not S[i] in num:
      flg = False
print('Yes' if flg else 'No')
