#include <stdio.h>
#include <string.h>
#define max_row 10000
#define max_col 100000
char a[max_row][max_col];
void backward(char *a) {
for (int i = 0; *(a + i) != 0; i++) {
if (*(a + i) == '<') {
if (i != 0) {
strcpy(a + i - 1, a + i + 1);
i -= 2;
}
else {
strcpy(a, a + 1);
i--;
}
}
}
return;
}
int main(void) {
int i, ans = 0, T;
char *a_finish = a[0], b[max_col], *a_p = a[0];
for (; ; a_finish += max_col) {
gets(a_finish);
if (strcmp(a_finish, "EOF") == 0) {
break;
}
backward(a_finish);
}
for (; ; a_p += max_col) {
gets(b);
if (strcmp(b, "EOF") == 0) {
break;
}
if (a_p >= a_finish) {
continue;
}
backward(b);
for (i = 0; (b[i] != 0) && (*(a_p + i) != 0); i++) {
ans += (*(a_p + i) == b[i]);
}
}
scanf("%d", &T);
printf("%d", (int)((double)ans / (double)T * 60.0 + 0.5));
return 0;
}