T = int(input())
x =[0]*T
s = "T"
for a in range(0,T):
    x[a] = int(input())
for i in range(0,T-1):
    if(x[i] != x[i+1]+1)and(x[i] != x[i+1]-1):
        s = "F"
        break
print(s)