STEPHEN TEKAJUOK AFTER the worst rains in living memory inundated her fields, South Sudan farmer Alexandra Karama is, like hundreds of thousands of her compatriots, staring hunger in the face. Her smallholding is located outside the western town of Mundri, one of the worst affected areas where swathes of crops have failed. "My groundnuts have all been swept by the water... Nothing is left, no sorghum (either)," Karama, a grandmother, told Reuters in Mundri town, where she has been forced to seek shelter at a U.N. compound. Like much of east Africa, South Sudan has been affected by unusually prolonged…