Gradually Increase Number Row - Python3

'''
Program to display followings:
1
1 2
1 2 3
1 2 3 4
1 2 3 4 5
'''

a=int(input("Enter the number of rows:"))
num=1
for i in range(0,a):
    num=1
    for j in range(0,i+1):
        print (num,end =" ")
        num=num+1
    print ("")

ScreenShot: