A, B = map(int, input().split())
S = input()
ans = "Yes"
digit = [ord('0')+i for i in range(10)]
if S[A] != "-":
  ans = "No"
if not all([c in digit for c in S[:A]]):
  ans = "No"
if not all([c in digit for c in S[B:]]):
  ans = "No"
print(ans)
