// ---------------- 1 ----------------
#include <stdio.h>
#include <math.h>


int main() {
    double a, x, y;
    for (a = 4; a < 6.1; a += 0.2) {
        for (x = 3; x <= 5; x += 0.5) {
            if (x != a) {
                y = sqrt(x * x + a * a) / (x - a);
                printf("\ta = %lf, x = %lf\n\ty = %lf\n", a, x, y);
            }
        }
    }
}
// ---------------- 2 ----------------
#include <stdio.h>
#include <math.h>


int main() {
    double e, x, c, result = 0;
    unsigned n = 1;
    scanf("%lf%lf", &x, &e);
    c = e;
    for(short digit = 1; c >= e; digit *= -1, ++n) {
        c = digit * pow(x, 2 * n - 1) / (4 * n * n - 1);
        result += c;
    }
    printf("%lf", result);
}

// ---------------- 3 ----------------
#include <stdio.h>

int main() {
    FILE* input = fopen("input.txt", "r");
    unsigned a, b;
    fscanf(input, "%u%u", &a, &b);
    int matrix[a][b];
    for (unsigned i = 0; i < a; ++i) {
        for (unsigned j = 0; j < b; ++j) {
            fscanf(input, "%i", &matrix[i][j]);
        }
    }
    fclose(input);
    FILE* output = fopen("output.txt", "w");
    for (unsigned i = 0; i < a; ++i) {
        for (unsigned j = 0; j < b; ++j) {
            fprintf(output, "%4i ", matrix[j][i]);
        }
        fprintf(output, "\n");
    }
    fclose(output);
}
// ---------------- 4 ----------------
#include <stdio.h>
#include <string.h>

int main() {
   char sentence[BUFSIZ];
   gets(sentence);
   FILE* output = freopen("output.txt", "w", stdout);
   char separators[] = " ,.";
   char* word = strtok(sentence, separators);
   while (word != NULL) {
       if (strlen(word) % 2 != 0) {
           printf("%s ", word);
       }
       word = strtok(NULL, separators);
   }
   fclose(output);
}