n=int(input()) x=str(input()) a=int(x[0]) s=a-1 c=1 for i in range(1,len(x)) : s*=i for j in range (1,len(x)) : c*=j for i in range(1,len(x)-1) : a=int(x[i]) ss=0 for j in range(i,len(x)) : b=int(x[j]) if a>b : ss+=1 c//=(len(x)-i) #print(c) ss*=c #print(ss) s+=ss s+=1 print(int(s))