Răspuns:
49
Explicație pas cu pas:
2302,2312,2322,2342,2352,2362,2372,2382,2392,2402,2412,2422,2432,2442,2452,2462,2472,2482,2492,2502,2512,2522,2532,2542,2552,2562,2572,2582,2592,2602,2612,2622,2632,2642,2652,2662,2672,2682,2692,2702,2712,2722,2732,2742,2752,2762,2772,2782,2792.