n = 10**2
print(n)
#We want to compute 1+2+3+...+n

#first solution
i = 1
s = 0
while i<=n:
    s = s+i
    i = i+1
    #print("i=", i, "s=", s)
print("Using while loop:")
print(s)



#second solution
s = 0
for i in range(1,n+1,1):
    s = s+i
print("Using for loop + range:")
print(s)


#third solution
print("Using Python's built-in sum")
print(sum(range(1,n+1,1)))
      

#fourth solution
print("Using Gauss' formula")
print((n*(n+1)//2))