a, b = map(int, input().split())
s = input()
import sys
if len(s) != a + b + 1:
  print('No')
else:
  for i in range(a):
    if !(s[i].isdigit()):
      print('No')
      sys.exit(0)
  for i in range(b):
    if !(s[len(a)+i+1].isdigit()):
      print('No')
      sys.exit(0)
  if s[len(a)] != '-':
    print('No')
  else:
    print('Yes')