P = list(range(2*10**5+1))
for i in range(2,2*10**5+1):
    if i*i>2*10**5:
        break
    for j in range(i*i,2*10**5+1,i):
        P[j] = P[i]
Q = []
for i in range(2,2*10**5+1):
    if P[i]==i:
        Q.append(i)
X = int(input())
Y = X
if X==1:
    print(2)
    print(1,2)
    print("b","g")
else:
    C = {}
    for p in Q:
        if X==1:break
        if X%p==0:
            cnt = 0
            while X%p==0:
                X //= p
                cnt += 1
            C[p] = cnt
    if X>1:
        print(-1)
    else:
        m = len(C)
        N = 0
        for p in C:
            N += (1+p)*C[p]
        if Y+1<N:
            print(Y+1)
            for i in range(1,Y+1):
                print(1,1+i)
            print("b"+"g"*Y)
        else:
            print(N)
            C = [0]+list(C.items())
            pre = 1
            n = 1
            col = []
            for i in range(1,m+1):
                for j in range(C[i][1]):
                    if n>1:
                        print(pre,n)
                    col.append("b")
                    cnt = 1
                    while cnt<C[i][0]+1:
                        print(n,n+cnt)
                        col.append("g")
                        cnt += 1
                    pre = n
                    n += cnt
            print(*col)