# Summe 1 + . . . . + n
# while-Schleife

n = int(input('n = '))

i = 1    # Initialisierung des Schleifenindex i
sum = 0  # Initialisierung der Summe

while i<= n:
    sum = sum + i
    i = i+1

print ('1 + . . . . +',n,' = ',sum)