import sys

sys.setrecursionlimit(10 ** 5)


def dfs(real_wishes, w, k, c):
    if real_wishes > w: return False
    if real_wishes+k == w:
        return True
    if k == 0: return False

    for new_k in range(1, k-c+1):
        if dfs(real_wishes + (k-1), w, new_k, c):
            return True
    
    return False

def main():
    w, k, c = map(int, input().split())
    print("yes" if dfs(0, w, k, c) else "no")
main()