n = int(input())

ok = 0
ng = n
while ng-ok > 1:
    mid = (ok+ng)//2
    if mid**2 <= n:
        ok = mid
    else:
        ng = mid

ans = []
for i in range(2*ok-1):
    ans.append(97+i%2)
q = n-ok*ok
for i in range(q):
    ans.append(120+i%3)

print("".join(map(chr,ans)))