#include<stdio.h>
#include<string.h>
#include<ctype.h>
int lengthoflastword(char*s)
{
    int len = strlen(s);
    for(int i=0;i<len;i++)
        if(!isalnum(s[i]) && !isspace(s[i]))
        {
            printf("Invalid input");
            return -1;
        }
        int count = 0;
        int i= len - 1;
        
        while(i>=0 && s[i]!= ' ')
        {
            i--;
        }
        while(i>=0 && s[i])!= ' ')
        {
            count++;
            i--;
        }
        return count;
}
int main()
{
    char s[21];
    fgets(s,sizeof(s),stdin);
    s[strcspn(s,"\n")]= 0;
    int result = lengthoflastword(s);
    if (result != -1)
    {
        printf("%d\n",result);
    }
    return 0;
}