#include <bits/stdc++.h>   using namespace std;   int a[] = {       0,    4784, 4194, 4003, 3920, 3831, 3791, 3726, 3667, 3669, 3591, 3642,       3612, 3532, 3554, 3507, 3500, 3517, 3449, 3496, 3432, 3462, 3406, 3394,       3376, 3378, 3445, 3362, 3368, 3371, 3305, 3369, 3386, 3336, 3320, 3302,       3273, 3356, 3286, 3307, 3284, 3327, 3291, 3247, 3251, 3306, 3241, 3278,       3231, 3271, 3248, 3239, 3184, 3227, 3204, 3235, 3210, 3216, 3191, 3211,       3222, 3193, 3206, 3234, 3157, 3149, 3191, 3188, 3193, 3225, 3192, 3182,       3138, 3152, 3135, 3106, 3167, 3211, 3130, 3141, 3137, 3125, 3129, 3135,       3122, 3125, 3160, 3154, 3168, 3106, 3117, 3076, 3149, 3118, 3135, 3063,       3171, 3091, 3103, 3099, 3075, 3087, 3126, 3071, 3086, 3114, 3074, 3101,       3069, 3091, 3080, 3080, 3101, 3067, 3111, 3079, 3117, 3093, 3089, 3103,       3073, 3040, 3054, 3122, 3079, 3021, 3024, 3098, 3068, 3057, 3013, 3014,       3077, 3020, 3073, 3038, 3027, 3039, 3044, 3061, 3012, 2998, 3043, 3054,       3066, 3018, 3025, 3037, 3035, 3015, 3010, 3004, 3014, 3018, 2931, 2994,       3015, 3025, 3032, 3075, 3031, 2990, 2994, 3030, 2994, 3050, 2997, 2973,       3008, 3017, 3034, 2998, 2962, 3052, 2980, 2996, 3025, 3000, 2994, 2973,       3022, 2961, 2981, 3039, 2964, 2968, 2941, 3016, 2992, 3014, 2978, 2983,       3006, 2970, 2968, 2999, 2936, 2985, 2983, 2950, 3034, 2953, 2964, 2930,       2950, 2965, 2996, 2968, 2960, 2962, 2952, 2972, 2933, 3012, 2982, 3002,       2904, 2965, 2963, 2974, 3012, 2915, 2921, 2947, 2908, 2934, 2998, 2925,       2951, 2971, 2936, 2986, 2949, 2951, 2958, 2936, 2930, 2957, 2895, 2926,       2934, 2899, 2971, 3011, 2951, 2937, 2925, 2916, 2968, 2931, 2927, 2944,       2913, 2902, 2936, 2912, 2925, 2955, 2939, 2936, 2912, 2935, 2905, 2928,       2956, 2968, 2923, 2953, 2902, 2938, 2928, 2928, 2902, 2886, 2942, 2873,       2980, 2886, 2911, 2920, 2922, 2968, 2876, 2924, 2904, 2952, 2885, 2910,       2924, 2901, 2928, 2887, 2887, 2961, 2911, 2882, 2896, 2897, 2874, 2941,       2958, 2898, 2926, 2916, 2933, 2873, 2969, 2886, 2907, 2938, 2845, 2855,       2898, 2883, 2900, 2902, 2887, 2889, 2877, 2905, 2879, 2901, 2891, 2867,       2867, 2869, 2906, 2888, 2893, 2870, 2921, 2878, 2910, 2914, 2864, 2879,       2898, 2841, 2919, 2943, 2856, 2817, 2837, 2899, 2823, 2901, 2878, 2824,       2888, 2880, 2906, 2855, 2854, 2907, 2902, 2862, 2859, 2918, 2890, 2835,       2847, 2898, 2844, 2923, 2857, 2884, 2917, 2840, 2875, 2831, 2880, 2907,       2916, 2859, 2861, 2831, 2841, 2871, 2854, 2898, 2849, 2905, 2896, 2903,       2868, 2835, 2845, 2853, 2926, 2874, 2849, 2832, 2876, 2859, 2885, 2887,       2853, 2913, 2828, 2842, 2820, 2900, 2805, 2866, 2860, 2877, 2834, 2852,       2923, 2817, 2850, 2840, 2884, 2796, 2860, 2885, 2826, 2842, 2842, 2843,       2799, 2817, 2871, 2909, 2841, 2853, 2791, 2809, 2854, 2815, 2832, 2818,       2866, 2800, 2872, 2877, 2865, 2774, 2846, 2881, 2890, 2847, 2805, 2869,       2789, 2850, 2828, 2844, 2850, 2846, 2827, 2821, 2783, 2882, 2855, 2823,       2845, 2853, 2821, 2840, 2792, 2822, 2788, 2859, 2846, 2819, 2805, 2890,       2830, 2846, 2881, 2755, 2890, 2829, 2813, 2862, 2820, 2835, 2828, 2871,       2810, 2840, 2826, 2778, 2865, 2835, 2837, 2809, 2800, 2840, 2826, 2836,       2807, 2829, 2834, 2822, 2843, 2815, 2806, 2861, 2805, 2786, 2842, 2792,       2813, 2841, 2840, 2817, 2827, 2795, 2816, 2780, 2799, 2796, 2897, 2789,       2820, 2738, 2852, 2791, 2818, 2863, 2787, 2765, 2826, 2773, 2820, 2823,       2817, 2784, 2812, 2770, 2814, 2856, 2793, 2778, 2781, 2822, 2779, 2809,       2850, 2793, 2835, 2765, 2790, 2760, 2869, 2785, 2801, 2769, 2866, 2861,       2767, 2812, 2767, 2790, 2765, 2841, 2805, 2816, 2811, 2808, 2894, 2762,       2769, 2810, 2756, 2848, 2802, 2760, 2762, 2776, 2802, 2837, 2832, 2802,       2813, 2785, 2757, 2828, 2785, 2791, 2765, 2781, 2835, 2755, 2835, 2779,       2784, 2802, 2765, 2765, 2800, 2756, 2746, 2808, 2797, 2802, 2800, 2830,       2795, 2793, 2772, 2783, 2822, 2839, 2768, 2826, 2800, 2797, 2776, 2769,       2727, 2790, 2774, 2821, 2716, 2761, 2788, 2755, 2812, 2854, 2782, 2796,       2789, 2746, 2762, 2767, 2807, 2770, 2774, 2784, 2805, 2744, 2805, 2772,       2761, 2768, 2844, 2807, 2778, 2792, 2812, 2842, 2775, 2773, 2728, 2792,       2757, 2783, 2777, 2831, 2752, 2829, 2711, 2844, 2745, 2803, 2774, 2780,       2752, 2791, 2809, 2749, 2806, 2771, 2777, 2801, 2768, 2725, 2786, 2728,       2779, 2792, 2809, 2820, 2767, 2745, 2771, 2768, 2815, 2729, 2783, 2791,       2766, 2807, 2753, 2769, 2811, 2743, 2764, 2783, 2807, 2713, 2813, 2769,       2777, 2820, 2728, 2741, 2748, 2765, 2791, 2760, 2745, 2781, 2788, 2755,       2741, 2739, 2746, 2767, 2767, 2808, 2735, 2778, 2787, 2766, 2695, 2826,       2731, 2794, 2743, 2777, 2765, 2769, 2780, 2801, 2754, 2789, 2751, 2768,       2691, 2752, 2778, 2740, 2795, 2771, 2750, 2779, 2710, 2718, 2741, 2764,       2799, 2749, 2788, 2741, 2785, 2768, 2735, 2761, 2728, 2759, 2777, 2809,       2775, 2738, 2771, 2786, 2776, 2731, 2760, 2702, 2774, 2749, 2760, 2765,       2724, 2747, 2798, 2763, 2766, 2758, 2767, 2749, 2717, 2700, 2758, 2733,       2747, 2734, 2766, 2764, 2765, 2728, 2757, 2705, 2792, 2683, 2754, 2773,       2739, 2720, 2747, 2781, 2726, 2769, 2756, 2734, 2698, 2765, 2732, 2771,       2769, 2752, 2724, 2721, 2765, 2766, 2733, 2806, 2754, 2717, 2729, 2773,       2737, 2774, 2734, 2757, 2797, 2772, 2680, 2716, 2745, 2736, 2758, 2746,       2748, 2776, 2777, 2723, 2669, 2760, 2689, 2758, 2748, 2750, 2718, 2809,       2824, 2664, 2749, 2717, 2774, 2775, 2713, 2685, 2758, 2725, 2767, 2724,       2710, 2719, 2785, 2782, 2755, 2715, 2762, 2700, 2695, 2778, 2724, 2706,       2752, 2740, 2747, 2702, 2700, 2739, 2716, 2792, 2717, 2765, 2704, 2700,       2783, 2750, 2743, 2771, 2747, 2744, 2710, 2765, 2729, 2760, 2638, 2781,       2735, 2739, 2725, 2708, 2779, 2769, 2706, 2729, 2717, 2718, 2690, 2762,       2688, 2692, 2720, 2759, 2756, 2727, 2739, 2683, 2736, 2710, 2697, 2731,       2724, 2806, 2707, 2693, 2649, 2741, 2725, 2700, 2751, 2724, 2765, 2710,       2749, 2752, 2714, 2760, 2747, 2754, 2670, 2699, 2730, 2717, 2736, 2731,       2699, 2677, 2697, 2714, 2789, 2778, 2702, 2705, 2677, 2701, 2761, 2749,       2699, 2781, 2755, 2697, 2699, 2733, 2710, 2769, 2736, 2699, 2701, 2727,       2757, 2706, 2747, 2669, 2727, 2700, 2722, 2754, 2726, 2714, 2734, 2735,       2687, 2730, 2669, 2725, 2745, 2688, 2729, 2722, 2737, 2691, 2722, 2728,       2683, 2699, 2772, 2725, 2659, 2731, 2676, 2769, 2683, 2680, 2721, 2697,       2737, 2704, 2708, 2709, 2735, 2721, 2714, 2721, 2663, 2718, 2695, 2745,       2691, 2684, 2749, 2713, 2707, 2723, 2704, 2712, 2669, 2763, 2668, 2701,       2737, 2719, 2696, 2749, 2769, 2676, 2723, 2729, 2683, 2746, 2688, 2735,       2624, 2698, 2700, 2729, 2684, 2704, 2676, 2692, 2779, 2710, 2719, 2744,       2724, 2705, 2699, 2697, 2697, 2727, 2685, 2734, 2674, 2712, 2714, 2699,       2716, 2680, 2709, 2679, 2696, 2732, 2704, 2712, 2661, 2702, 2735, 2695,       2663, 2726, 2645, 2758, 2735, 2696, 2755, 2696, 2668, 2744, 2717, 2695,       2622, 2708, 2712, 2711, 2715, 2747, 2700, 2745, 2701, 2684, 2720, 2688,       2749, 2726, 2652, 2759, 2665, 2714, 2716, 2700, 2764, 2701, 2644, 2677,       2656, 2727, 2658, 2743, 2695, 2723, 2693, 2705, 2698, 2657, 2731, 2674,       2698, 2705, 2761, 2728, 2717, 2743, 2722, 2699, 2698, 2633, 2686, 2703,       2750, 2680, 2662, 2714, 2716, 2656, 2696, 2685, 2655, 2694, 2652, 2671,       2653, 2668, 2713, 2685, 2697, 2685, 2642, 2782, 2694, 2664, 2675, 2710,       2689, 2736, 2651, 2702, 2698, 2673, 2705, 2632, 2732, 2707, 2682, 2684,       2726, 2622, 2688, 2670, 2657, 2680, 2711, 2694, 2654, 2722, 2697, 2681,       2730, 2674, 2673, 2666, 2701, 2717, 2717, 2692, 2681, 2698, 2710, 2670,       2626, 2674, 2696, 2719, 2689, 2699, 2690, 2674, 2727, 2675, 2688, 2687,       2677, 2688, 2640, 2709, 2627, 2691, 2664, 2714, 2664, 2724, 2675, 2733,       2680, 2641, 2684, 2706, 2717, 2611, 2696, 2662, 2693, 2712, 2636, 2651,       2719, 2685, 2673, 2689, 2708, 2729, 2677, 2678, 2735, 2693, 2703, 2661,       2710, 2680, 2686, 2656, 2732, 2674, 2674, 2713, 2699, 2670, 2640, 2689,       2709, 2646, 2717, 2646, 2705, 2690, 2677, 2660, 2660, 2664, 2721, 2676,       2689, 2675, 2697, 2709, 2616, 2671, 2714, 2675, 2653, 2661, 2717, 2742,       2662, 2656, 2688, 2716, 2658, 2701, 2675, 2681, 2678, 2725, 2649, 2679,       2656, 2641, 2720, 2708, 2735, 2734, 2665, 2643, 2719, 2659, 2670, 2718,       2679, 2676, 2742, 2578, 2697, 2638, 2646, 2626, 2720, 2656, 2628, 2697,       2719, 2666, 2710, 2658, 2678, 2715, 2704, 2688, 2683, 2702, 2658, 2630,       2700, 2665, 2684, 2711, 2646, 2670, 2707, 2655, 2673, 2690, 2613, 2737,       2674, 2584, 2703, 2695, 2667, 2643, 2651, 2645, 2710, 2661, 2671, 2699,       2691, 2720, 2641, 2677, 2670, 2659, 2695, 2709, 2646, 2677, 2631, 2709,       2585, 2655, 2687, 2638, 2653, 2637, 2667, 2635, 2686, 2732, 2672, 2695,       2658, 2631, 2658, 2643, 2629, 2693, 2671, 2705, 2686, 2665, 2707, 2629,       2577, 2650, 2669, 2590, 2681, 2662, 2688, 2649, 2647, 2705, 2684, 2653,       2705, 2636, 2693, 2726, 2693, 2684, 2680, 2639, 2727, 2724, 2652, 2609,       2662, 2643, 2669, 2656, 2619, 2598, 2707, 2612, 2648, 2696, 2710, 2609,       2703, 2671, 2698, 2657, 2664, 2699, 2642, 2671, 2706, 2635, 2615, 2669,       2659, 2671, 2639, 2707, 2627, 2709, 2687, 2657, 2649, 2654, 2690, 2657,       2680, 2672, 2671, 2681, 2701, 2645, 2652, 2704, 2605, 2653, 2655, 2684,       2647, 2678, 2649, 2669, 2639, 2646, 2654, 2694, 2672, 2663, 2667, 2676,       2652, 2670, 2650, 2653, 2671, 2662, 2678, 2697, 2616, 2647, 2687, 2675,       2678, 2603, 2630, 2639, 2687, 2683, 2618, 2646, 2652, 2661, 2667, 2639,       2652, 2670, 2611, 2641, 2669, 2623, 2690, 2642, 2670, 2625, 2704, 2671,       2628, 2643, 2655, 2632, 2650, 2668, 2629, 2641, 2667, 2615, 2617, 2664,       2636, 2658, 2655, 2646, 2633, 2628, 2703, 2639, 2693, 2641, 2604, 2596,       2601, 2666, 2623, 2663, 2670, 2633, 2641, 2687, 2627, 2609, 2669, 2642,       2706, 2688, 2670, 2701, 2618, 2679, 2643, 2645, 2637, 2628, 2658, 2649,       2602, 2682, 2654, 2660, 2614, 2679, 2584, 2662, 2711, 2637, 2617, 2640,       2652, 2730, 2665, 2639, 2663, 2658, 2651, 2670, 2666, 2645, 2655, 2599,       2608, 2677, 2652, 2698, 2651, 2620, 2617, 2634, 2659, 2678, 2590, 2653,       2667, 2648, 2535, 2634, 2616, 2632, 2686, 2653, 2650, 2596, 2645, 2672,       2691, 2602, 2667, 2659, 2648, 2588, 2695, 2645, 2641, 2673, 2653, 2634,       2603, 2717, 2621, 2725, 2641, 2626, 2588, 2653, 2646, 2635, 2639, 2621,       2625, 2611, 2657, 2662, 2673, 2648, 2648, 2649, 2663, 2634, 2623, 2645,       2631, 2678, 2642, 2628, 2692, 2710, 2639, 2667, 2661, 2612, 2611, 2695,       2629, 2616, 2652, 2671, 2597, 2648, 2621, 2587, 2639, 2644, 2632, 2679,       2610, 2602, 2632, 2647, 2682, 2559, 2641, 2671, 2658, 2697, 2604, 2614,       2647, 2604, 2650, 2646, 2646, 2636, 2610, 2706, 2584, 2628, 2629, 2673,       2640, 2632, 2628, 2644, 2636, 2631, 2626, 2708, 2594, 2651, 2628, 2703,       2671, 2641, 2672, 2683, 2635, 2597, 2638, 2646, 2583, 2677, 2662, 2624,       2648, 2644, 2618, 2607, 2583, 2660, 2623, 2671, 2630, 2665, 2643, 2641,       2621, 2603, 2666, 2628, 2604, 2665, 2652, 2638, 2644, 2624, 2638, 2632,       2644, 2631, 2622, 2627, 2694, 2621, 2681, 2641, 2660, 2658, 2572, 2626,       2654, 2635, 2636, 2625, 2640, 2648, 2620, 2558, 2675, 2651, 2618, 2629,       2651, 2668, 2619, 2646, 2662, 2613, 2605, 2621, 2645, 2628, 2599, 2649,       2657, 2616, 2613, 2654, 2640, 2605, 2670, 2652, 2635, 2604, 2691, 2610,       2617, 2614, 2647, 2652, 2668, 2660, 2647, 2621, 2604, 2629, 2623, 2649,       2630, 2706, 2579, 2672, 2618, 2629, 2657, 2641, 2614, 2652, 2697, 2659,       2630, 2645, 2610, 2622, 2607, 2623, 2645, 2600, 2634, 2599, 2583, 2645,       2587, 2671, 2646, 2613, 2604, 2649, 2635, 2599, 2693, 2620, 2667, 2622,       2545, 2597, 2604, 2640, 2635, 2593, 2605, 2656, 2627, 2587, 2623, 2633,       2631, 2654, 2618, 2605, 2624, 2623, 2631, 2670, 2639, 2629, 2648, 2645,       2655, 2615, 2635, 2625, 2669, 2625, 2647, 2603, 2584, 2608, 2612, 2620,       2658, 2653, 2637, 2584, 2617, 2641, 2602, 2630, 2617, 2668, 2619, 2626,       2671, 2618, 2635, 2663, 2576, 2557, 2642, 2603, 2650, 2646, 2688, 2567,       2614, 2627, 2614, 2674, 2616, 2562, 2615, 2640, 2691, 2630, 2635, 2638,       2614, 2620, 2625, 2621, 2681, 2622, 2607, 2588, 2649, 2553, 2606, 2592,       2568, 2565, 2591, 2665, 2600, 2595, 2623, 2640, 2596, 2578, 2617, 2571,       2625, 2611, 2602, 2605, 2640, 2629, 2633, 2666, 2626, 2668, 2613, 2665,       2619, 2558, 2603, 2629, 2635, 2676, 2599, 2623, 2619, 2632, 2611, 2613,       2627, 2634, 2583, 2631, 2627, 2640, 2649, 2618, 2640, 2565, 2616, 2620,       2627, 2623, 2648, 2597, 2629, 2630, 2587, 2588, 2621, 2645, 2620, 2580,       2596, 2648, 2584, 2606, 2572, 2656, 2548, 2598, 2602, 2584, 2610, 2628,       2630, 2570, 2623, 2592, 2653, 2630, 2635, 2654, 2635, 2555, 2592, 2598,       2584, 2638, 2697, 2592, 2614, 2606, 2566, 2610, 2685, 2664, 2686, 2616,       2547, 2628, 2632, 2562, 2638, 2607, 2588, 2679, 2650, 2604, 2637, 2614,       2562, 2613, 2620, 2632, 2657, 2626, 2654, 2589, 2640, 2577, 2635, 2566,       2606, 2645, 2569, 2610, 2630, 2616, 2670, 2630, 2565, 2646, 2601, 2626,       2629, 2592, 2598, 2551, 2627, 2661, 2621, 2654, 2576, 2643, 2614, 2591,       2583, 2618, 2596, 2586, 2585, 2590, 2664, 2601, 2587, 2629, 2608, 2635,       2576, 2620, 2625, 2530, 2660, 2628, 2634, 2562, 2598, 2640, 2621, 2636,       2628, 2596, 2609, 2543, 2619, 2562, 2625, 2591, 2584, 2619, 2585, 2615,       2639, 2587, 2592, 2605, 2573, 2563, 2662, 2659, 2607, 2673, 2641, 2578,       2607, 2596, 2664, 2614, 2625, 2557, 2613, 2617, 2555, 2603, 2594, 2615,       2681, 2632, 2633, 2644, 2561, 2636, 2581, 2631, 2611, 2595, 2572, 2635,       2632, 2620, 2615, 2641, 2593, 2590, 2675, 2620, 2589, 2600, 2623, 2609,       2606, 2624, 2561, 2594, 2631, 2622, 2623, 2577, 2581, 2603, 2574, 2639,       2616, 2620, 2640, 2642, 2627, 2587, 2637, 2612, 2603, 2621, 2599, 2606,       2639, 2645, 2617, 2633, 2618, 2596, 2596, 2592, 2600, 2616, 2581, 2590,       2606, 2598, 2646, 2576, 2545, 2591, 2636, 2556, 2604, 2636, 2635, 2599,       2575, 2527, 2616, 2607, 2610, 2572, 2589, 2643, 2545, 2650, 2608, 2615,       2585, 2627, 2536, 2603, 2587, 2612, 2643, 2597, 2654, 2544, 2610, 2605,       2558, 2618, 2553, 2616, 2604, 2688, 2559, 2577, 2581, 2642, 2619, 2550,       2609, 2642, 2613, 2616, 2544, 2599, 2675, 2639, 2594, 2547, 2645, 2595,       2618, 2602, 2551, 2637, 2667, 2596, 2600, 2590, 2515, 2615, 2577, 2635,       2647, 2605, 2590, 2568, 2592, 2657, 2672, 2627, 2578, 2544, 2563, 2560,       2609, 2593, 2617, 2660, 2562, 2638, 2567, 2575, 2599, 2599, 2593, 2636,       2649, 2665, 2569, 2608, 2638, 2585, 2626, 2563, 2547, 2525, 2543, 2581,       2597, 2595, 2608, 2572, 2570, 2555, 2581, 2648, 2624, 2545, 2632, 2578,       2625, 2564, 2578, 2629, 2569, 2579, 2576, 2568, 2637, 2630, 2598, 2566,       2595, 2598, 2625, 2614, 2621, 2578, 2531, 2608, 2580, 2594, 2595, 2611,       2568, 2640, 2577, 2612, 2635, 2571, 2602, 2606, 2588, 2624, 2567, 2611,       2638, 2590, 2604, 2549, 2585, 2550, 2576, 2601, 2619, 2600, 2604, 2541,       2600, 2590, 2599, 2578, 2553, 2573, 2606, 2610, 2599, 2637, 2594, 2587,       2571, 2644, 2591, 2621, 2633, 2570, 2563, 2578, 2592, 2601, 2644, 2581,       2595, 2577, 2598, 2586, 2658, 2609, 2596, 2578, 2595, 2587, 2594, 2578,       2663, 2561, 2584, 2609, 2576, 2622, 2624, 2583, 2614, 2583, 2551, 2651,       2613, 2579, 2588, 2544, 2591, 2601, 2582, 2641, 2540, 2623, 2542, 2584,       2560, 2632, 2564, 2631, 2621, 2618, 2631, 2558, 2556, 2615, 2587, 2561,       2664, 2597, 2603, 2597, 2599, 2524, 2594, 2593, 2606, 2552, 2564, 2520,       2597, 2599, 2555, 2526, 2599, 2628, 2572, 2602, 2503, 2642, 2538, 2596,       2598, 2623, 2578, 2635, 2568, 2525, 2635, 2589, 2562, 2594, 2618, 2617,       2581, 2673, 2595, 2572, 2616, 2616, 2590, 2605, 2597, 2577, 2579, 2587,       2561, 2512, 2621, 2566, 2574, 2584, 2601, 2571, 2575, 2611, 2579, 2573,       2604, 2519, 2590, 2620, 2570, 2532, 2579, 2558, 2615, 2538, 2613, 2631,       2623, 2585, 2571, 2596, 2593, 2602, 2591, 2578, 2604, 2565, 2600, 2518,       2591, 2576, 2585, 2570, 2596, 2570, 2601, 2597, 2567, 2556, 2561, 2626,       2613, 2635, 2627, 2563, 2540, 2566, 2585, 2555, 2590, 2597, 2547, 2579,       2545, 2645, 2584, 2537, 2548, 2599, 2578, 2506, 2602, 2605, 2552, 2587,       2594, 2621, 2607, 2585, 2665, 2548, 2564, 2577, 2567, 2567, 2600, 2615,       2574, 2607, 2582, 2636, 2556, 2621, 2605, 2585, 2560, 2534, 2645, 2589,       2559, 2602, 2592, 2557, 2601, 2583, 2603, 2588, 2559, 2557, 2566, 2583,       2545, 2610, 2664, 2557, 2633, 2632, 2579, 2561, 2573, 2560, 2531, 2582,       2625, 2598, 2546, 2595, 2580, 2608, 2603, 2611, 2602, 2612, 2550, 2559,       2586, 2620, 2578, 2593, 2597, 2548, 2523, 2576, 2549, 2597, 2585, 2576,       2598, 2607, 2582, 2582, 2600, 2582, 2642, 2580, 2620, 2575, 2572, 2585,       2590, 2561, 2551, 2569, 2567, 2579, 2628, 2589, 2607, 2670, 2572, 2547,       2571, 2615, 2593, 2617, 2612, 2560, 2588, 2563, 2533, 2568, 2614, 2581,       2531, 2573, 2616, 2597, 2598, 2556, 2562, 2583, 2545, 2651, 2578, 2528,       2611, 2613, 2626, 2587, 2587, 2583, 2607, 2572, 2614, 2555, 2598, 2565,       2530, 2584, 2514, 2575, 2550, 2613, 2543, 2600, 2559, 2584, 2566, 2555,       2630, 2571, 2532, 2594, 2576, 2637, 2525, 2525, 2588, 2594, 2644, 2581,       2547, 2601, 2621, 2561, 2580, 2582, 2606, 2529, 2541, 2537, 2561, 2567,       2559, 2521, 2590, 2595, 2622, 2597, 2584, 2592, 2540, 2587, 2544, 2535,       2554, 2568, 2569, 2530, 2610, 2603, 2621, 2591, 2525, 2556, 2564, 2589,       2597, 2596, 2557, 2548, 2533, 2579, 2538, 2577, 2524, 2554, 2618, 2604,       2598, 2570, 2577, 2580, 2604, 2582, 2608, 2563, 2589, 2533, 2610, 2622,       2566, 2523, 2623, 2517, 2561, 2610, 2569, 2542, 2625, 2566, 2561, 2577,       2596, 2565, 2534, 2620, 2601, 2516, 2568, 2553, 2598, 2562, 2595, 2560,       2544, 2614, 2525, 2592, 2595, 2599, 2584, 2531, 2591, 2545, 2525, 2575,       2561, 2529, 2613, 2555, 2559, 2525, 2600, 2555, 2574, 2554, 2571, 2518,       2596, 2583, 2646, 2518, 2611, 2521, 2589, 2558, 2544, 2589, 2647, 2557,       2524, 2557, 2520, 2556, 2586, 2625, 2539, 2619, 2554, 2598, 2580, 2569,       2554, 2478, 2581, 2583, 2580, 2559, 2573, 2543, 2564, 2551, 2585, 2562,       2568, 2558, 2612, 2543, 2631, 2578, 2565, 2570, 2556, 2554, 2569, 2610,       2571, 2527, 2584, 2553, 2596, 2603, 2537, 2492, 2529, 2567, 2641, 2560,       2573, 2555, 2591, 2527, 2580, 2586, 2526, 2556, 2574, 2510, 2574, 2552,       2555, 2608, 2551, 2643, 2599, 2567, 2564, 2588, 2557, 2556, 2541, 2577,       2578, 2606, 2524, 2557, 2603, 2543, 2562, 2617, 2547, 2598, 2578, 2532,       2463, 2549, 2566, 2583, 2589, 2604, 2588, 2545, 2569, 2540, 2573, 2540,       2637, 2546, 2537, 2577, 2596, 2608, 2601, 2611, 2585, 2546, 2571, 2520,       2516, 2543, 2603, 2584, 2601, 2557, 2567, 2597, 2577, 2555, 2515, 2547,       2550, 2524, 2530, 2600, 2570, 2615, 2543, 2556, 2552, 2583, 2552, 2564,       2557, 2570, 2599, 2573, 2547, 2605, 2551, 2559, 2594, 2544, 2595, 2533,       2541, 2538, 2574, 2568, 2585, 2553, 2570, 2539, 2551, 2570, 2516, 2531,       2553, 2575, 2600, 2642, 2566, 2516, 2547, 2562, 2541, 2616, 2557, 2544,       2528, 2567, 2564, 2525, 2635, 2538, 2576, 2541, 2591, 2596, 2582, 2476,       2567, 2543, 2511, 2537, 2530, 2511, 2570, 2599, 2531, 2544, 2620, 2530,       2558};   int ans = 0;   int powmod(int a, int b, int p) {     int res = 1;     while (b)       if (b & 1) {         res = int(res * 1ll * a % p);         --b;       } else {         a = int(a * 1ll * a % p);         b >>= 1;       }     return res;   }   bool check(int m) {     int s = 0, t = m - 1, x, a = ((rand() * rand()) % (m - 3)) + 2;     while (!(t & 1)) {       ++s;       t >>= 1;     }     x = powmod(a, t, m);     if (x == 1 || x == m - 1) return true;     --s;     while (s--) {       x = (x * 1ll * x) % m;       if (x == 1) return false;       if (x == m - 1) return true;     }     return false;   }   bool test(int x, int r = 30) {     if (x == 2 || x == 3) return true;     if (x == 1 || !(x & 1)) return false;     bool ok = true;     while (r-- && ok) ok &= check(x);     return ok;   }   int main() {     int l, r;     cin >> l >> r;     if (l == 1 && r >= 2 || l == 2) ++ans;     int b1 = l / 100000 + 1;     for (int i = l; i <= b1 * 100000 && i <= r; i++)       if (test(i) && (i % 4 == 1)) ++ans;     for (int i = b1 + 1; i * 100000 <= r; i++) {       ans += a[i];       b1 = i;     }     for (int i = b1 * 100000; i <= r; i++)       if (test(i) && (i % 4 == 1)) ++ans;     cout << ans;     return 0;   }