def main():
import sys
data = sys.stdin.read().strip().split()
if len(data) != 2:
return
X, Y = data
X = X.strip()
Y = Y.strip()
order = {"Ocelot": 0, "Serval": 1, "Lynx": 2}
if X not in order or Y not in order:
print("No")
return
print("Yes" if order[X] >= order[Y] else "No")
if __name__ == "__main__":
main()
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