Составить программу, которая по введенному значению 1, 2, 3, 4 вычисляет площадь треугольника:

Если любой, то:
My heart's in the Highlands, my heart is not here, 
My heart's in the Highlands, a-chasing the deer; 
Chasing the wild-deer, and following the roe, 
My heart's in the Highlands, wherever I go.

Farewell to the Highlands, farewell to the North, 
The birth-place of Valour, the country of Worth ; 
Wherever I wander, wherever I rove, 
The hills of the Highlands for ever I love. 

Farewell to the mountains, high-cover'd with snow, 
Farewell to the straths and green vallies below; 
Farewell to the forests and wild-hanging woods, 
Farewell to the torrents and loud-pouring floods. 

My heart's in the Highlands, my heart is not here, 
My heart's in the Highlands, a-chasing the deer; 
Chasing the wild-deer, and following the roe, 
My heart's in the Highlands, wherever I go.

Robert Burns.