#include <stdio.h>
#include <string.h>
 
char a[205], b[205];
 
int main()
{
    int k, ans;
    char *p, *q, *wp, *wq;
    char *s[3] = { "IDENTICAL", "CLOSE", "DIFFERENT" };
 
    while (scanf("%s", a) && a[0] != '.') {
        scanf("%s", b); p = a, q = b; ans = -1, k = 0;
        while (*p && *q) {
            if (*p != *q) { ans = 2; break; }
            if (*p == '"') { wp = ++p, wq = ++q;
                while (*p != '"') p++;
                while (*q != '"') q++;
                *p = *q = 0;
                k += 1 - (strcmp(wp, wq) == 0);
                if (k > 1) { ans = 2; break; }
            }
            p++, q++;
        }
        if (ans < 0) if (*p == *q) ans = k; else ans = 2;
        puts(s[ans]);
    }
    return 0;
}
