// import chie template :) {{{
import std.stdio,
       std.algorithm,
       std.array,
       std.string,
       std.math,
       std.conv,
       std.range,
       std.container,
       std.bigint,
       std.ascii;
// }}}

void main() {
  int[] t = readln.chomp.split.to!(int[]);
  dchar[] s = readln.chomp.to!(dchar[]);
  if (s.length != t[0] + t[1] + 1) {
    writeln("No");
    return;
  }
  uint idx = 0;
  for (; idx < t[0]; ++idx) {
    if (!s[idx].to!string.isNumeric) {
      writeln("No");
      return;
    }
  }
  if (s[idx] != '-') {
    writeln("No");
    return;
  }
  ++idx;
  for (; idx < s.length; ++idx) {
    if (!s[idx].to!string.isNumeric) {
      writeln("No");
      return;
    }
  }

  writeln("Yes");
}
